RIGA, October 20 (RIA Novosti) - Latvian firms affected by Moscow's decision Friday to impose a temporary ban on deliveries of canned fish to Russia called the move a purely protectionist measure intended to cut their share of the Russian market.

Russia imposed a temporary ban on deliveries of canned fish produced by two factories in Latvia, Brivais Vilnis and Gamma-A, due to high levels of a dangerous substance allegedly detected in their products, the Russian Agriculture Ministry said Friday.

The ministry said: "Due to the detection of benzopyrene in quantities exceeding the set norm in tinned fish produced at the Gamma-A LV 44Z and Brivais Vilnis LV 28 Z fish-processing enterprises in Latvia, imports of canned fish from these companies will be temporarily banned as of October 20, 2006, pending further instructions."

"Heightened interest in our products has been motivated by competition," said Arnolds Babris, board chairman of Brivais Vilnis.

The two companies account for the 30% of the Russian canned fish market.

Both firms said benzopyrene, found by experts from Russia's Federal Service for Veterinary and Phytosanitary Oversight, is an inevitable result of the industrial process of frying and smoking fish, and that Russia's standards for this substance are five time that in the European Union.

According to Russian regulations, a maximum of one milligram of benzopyrene is allowed per kilogram of food products, whereas the EU norm is 5 milligrams per kilogram.

Babris said he does not exclude the possibility that experts found excessive levels of benzopyrene in Russian-made bootleg products.

"We have bought several small consignments of canned fish in Moscow and Kaliningrad for analysis," he said.

Restrictions imposed by Russian authorities on food imports, including United States poultry, Moldovan and Georgian wines, and Ukrainian meat, have been a source of tension in bilateral relations with these countries.